Control circuit for shaft positioning system



Feb. 7, 1939. R. E. SAMUELSON CONTROL CIRCUIT FOR SHAFT POSITIONINGSYSTEM Filed Dec. 24, 1957 2 Sheets-Sheet 1 R. E. SAMUELSON 2 Sheet ssheet 2 Filed D90. 24, 1937 W ,7. v M w M g A u CUM m 4 M Feb. 7, 1939.

CONTROL CIRCUIT FOR SHAFT POSITIONING SYSTEM Patented Feb. 7, 1939-PATENT OFFICE" ooN'raol. cnwm'r FOR snsr'r rosmo ma srs'rm Robert E.Samuelson, Cedar Rapids. Iowa, assignor to Arthur A. Cedar Rapids, IowaApplication December 24, 1937, Serial No. 181910:

8 Claims. (cl. 172-239) My invention relates broadly to automatic shaftpositioning systems and more particularlyrto a control circuit for shaftpositioning devices of. a type adapted to establish a shaft in positionin accordance with the direction and degree of rotation of a controllingelement.

A shaft positioning device of the type controllable by the circuit of myinvention is shown in certain figures in the accompanying drawings, andforms the subject matter of a copending application filed by Arthur A.Collins, Serial No. 180,658 filed December 18, 1937, for Shaftpositioning device. However, the circuit ,of my invention is adaptableto any device wherein a desired setting may be established withinpredetermined limits 'of angular movement in a single direction orsuccessive phases of I predetermined angular movement in oppositedirections.

One of the objects of my invention is to provide a control circuit for ashaft positioning system employing a single reversible driving motor forrotating the shaft.

Another object of my invention, is to provide a control circuit for ashaft positioning system adapted to establish a shaft in a selected oneof a plurality :of predetermined positions in accordance with a seriesof electrical impulses such as ,are produced by operation of a dialswitch.

A further object of my invention is to provide a control circuitcomprising animpulse actuating switch and control relays includingrelays having different time constants for energizing a reversible motorin accordance with the set and desired positions of a controlled shaftdriven by the motor.

Still another object of my invention is to provide a control circuitnormally deenergized but operative upon the actuation of a dial typeimpulse switch in a predetermined series of operations with respect tothe energizing circuits of a reversible motorin accordance with thenumber of impulses derived from the dial type switch.

A still further object of my invention is to provide a drum type controlswitch driven by a reversible motor and having a plurality of contactsconnected in a control system and adjustable in accordance withpredetermined degrees of rotation required of the motor.

Still another object of my invention is to provide a control circuitemploying a selector switch and a pair of differently timed slow releaserelays for controllin a sequence of operations in combination withforward and reverse motor control relays operative in connection with adrum typeswitch driven by the motor shaft, the control aircuitfunctioning to determine automatically the degree and direction ofangular rotation of the motor shaft. g

Other and further objects of my invention reside in the elements and thecircuit connections disclosed as hereinafter more fully set forth withreference to the accompanying drawings, in

which:

. Figure l is a schematic diagram of the control circuit of myinvention, indicating the arrange- 1 ment of the single driving motorwith respect to the shafts to be positioned; Figs. 2 and 3 arelongitudinal and cross-sectional views, respectively, of one form of apratus-to which thecontrol circuitof my inveri' on is adapted forautomatic 15 shaft positioning, operations; and Fig. 4 shows agroup oflinear diagrams illustrating the variations in direction and extent ofrotation required for transfers from one position to another in thecontrolled shafts.

device comprising the clutch plate H5, rotatable with but longitudinallyslidable on the shaft no, and is continuously urged by a spring insurface contact with a clutch plate driving member Ill,

constituted as a wheel gear driven by a worm gear I20 on the shaft II.The driving member ill is rotatable with respect to the shaft H0, and

in such action there is relative movement between the driving member liland the clutch plate H5.

The shaft III is stopped in desired position by the abutment againstapre-set fixed stop of one of two stop lugs carried on the opposite endsof an arm H8, which is radially shiftable but nonrotatable with respectto the clutch plate 5. The stop lugs are in offset planes and there aretwo fixed stops in the plane of each stop lug on the arm H8, asindicated in Fig. 3. The stop arm is shiftable radially to project oneorthe other of the stop lugs for engagement with one of .its coactingstops, depending upon the direction of rotation of the arm H8. The meansdisclosed for shifting the arm ill comprises a pin iii fixed in the armand projecting axially through the clutch plate ll! intoa groove III inthe clutch plate driving member Ill. As shown in Fig. 3, the groove I24is substantially spiral in form for a 360 portion b-d, with but a smallradial displacement, however; then for a 180 portion, d, c,

then is a substantial radial displacement, suillcient, in coaction withthe pin III, to cause the t stop arm IIB'to be shifted radially forprojecting theopposite stop lug; and then for a 360 portion e-a there isonly a small radial displacement as the groove spirals inwardly. Overrun90 portions are provided at a-b and a-'-h, but do not enter into thedefinite operation of the system. It willbe understood that the pin IIIremains relatively fixed in the-groove I24 when clutch plate II! and thedriving gear member-Hirotate together, and shiiting'oi the stop arm IIIcan only be eifected when the arm is stopped by abutment of theprojected stop lug against one of its coacting stops, the same stop lugbeing retracted, as the arm shifts radially, until it will clear theparticular stop engaged.

Thus, by limiting the degree of rotation of the gear H4 in a givendirection or directions, one or the other of the stop lugs on arm II8will be rotated into the range of adjustmenttof one of its coactingstops, the shaft IIII being stopped in determined position while thegear I completes its prescribed limited rotation. The diagrams shown inFig. 4 indicate the various prescribed motor operations effective tochange the position of the shaft III! to another position, whichoperations are automatically controlled by the control circuit of myinvention.

In construction, several of the positioning-devices are mounted togetherand driven by a common shaft II through separate worm gears I20. Poweris furnished to shaft I I by motor III, which also drives throughsuitable gearing, a drum type positioning switch I2 which consists oftwo com mutator segments I2a and I2c separated by small insulatingsegments I2b and I 2d. Bearing on these segments are contacts I'2e, f,a, and 71;, arranged in an arc of less than 180 degrees, commutatorsegments I2a and I20 being of equal extent. The positions of contacts I2e, 1, a and h, g

and the relative gear ratios between shaft II, switch I2 and gears I I4,are such that when insulating segment I2b is opposite contacts I2e, f, gand h, in succession, gears I will be at relative positions of zero,360, 720, and 1080 degrees, respectively,-with pins III in the groovesI24 at points b, d, e and a.

It will be noted that although points it and e in the grooves I24 arebut 180 displaced, a rotation of 360 of the gears H4 is prescribed. Thisis required in the apparatus disclosed because in thus effecting theshifting of the arm H8, the newly projected stop ing is 180 furtherdisplaced on the circumference of the gear. The additional 180 rotationof the gear is prescribed,

therefore, to bring the newly projected stop ing into the same relativeposition occupied by the formerly projected lug, in order that theoperation may proceed definitely. Dining the additional 180 rotation ofthe gear Ill, or some equivalent rotation during the complete cycle ofoperation, there is no relative movement of the pins III in the groovesI 24, so that the pins will at all times be within the positive limits band g of the grooves. may be driven through 1080 degrees of rotation,

the pins II, will at no time have more than 900 degrees of positiverelative movement with .respect to the gears, and will have the full 900degrees displacement only when positions one and four are at the extremeopposite ends of the adjustable range of positions for setting theshafts.

As will be seen in Figs. 1 and 4, in order to change from position #1 toposition #4, insulating segment I2b is rotated from contact I2e, the

Thus, although the gears 4' position shown, to contact I'2'h, duringwhich movement gears III will move through 1080 degrees in the onedirection; and pins III may shift through 900 degrees, relative to thegears Ill or may travel with the gears in some instances, to such anextent that there is but 540 degrees relative movement, the minimum, inwhich the pin shifts only from point 0 to point I, the gear Inevertheless completingthe full 1080 degrees prescribed. Regardless,therefore, of the setting of the stops and the actual movement of theshafts 0, my invention concerns the control of the motor I 0 throughprescribed degrees of rotation in one direction or partly in oppositedirections, the shafts I I0 being-automatically set within the limits ofthe prescribed operation.

Accordingly, to shift from position #1 to position #3, insulatingsegment I2!) is rotated from contact I2e to contact I2h, as in shiftingto pov:

sition #4, but the operation in this instance is continued, motor I0being reversed and insulating contact I2b is rotated back to contactI29, whereupon the operation is terminated. And to shift from position#i to position #2, insulating segment I2b is rotated to contact I2],whereupon the operation is complete. In the latter instance, theoperation corresponds to 360 rotation of gears H4 in one direction. Inthe former instance, the operation included the 1080 rotation toposition #4 and a further rotation of 360 in the reverse direction ofgears ill to reach position #3. Other positions as indicated in Fig. 4should be apparent from the foregoing.

Referring now to Fig. 1, I employ as a typical manual control theordinary telephone dial by which selection of positions is obtained bydialing a digit corresponding to the desired .position. Minor switch I5is of the ordinary telephone type and has contacts I 5a, b, c and d,which correspond to the four desired positions. The minor switch arm lieis stepped up to the desired contact by pulses supplied to a rotatingmagnet I8, and is returned to the home or oil-normal position byapplicatoin of current to a release magnet I1. Ofi-normal contacts I51and g are open with. the minor switch arm I 5c in the normal position.Telephone dial I4 is supplied with impulse springs Ida and b andofi-normal springs c, d, and e. A slowrelease relay I8, having a releasetime of approximately .05 second, is pro,- vided with normally opencontacts I81; and b, and two sets of two-way contacts I8c, d, e, andI8j, g, h. A slow release relay I8, having a release time of .250second, is provided with contacts I9a and b which are normally open, aswell as normally closed contacts I90 and d. The diil'erently timed slowrelease'relays I8 and I9 control the sequence of operation inthecircuit.

Relays 20 and 2I control motor I0 through con- I 24 is applied to theshaft of motor" to secure quick stopping, and is controlled by the motorcontrol relays 20, 2I, in accordance with the operation of -the motor.,M

The circuit connections in; outline are as fol-- lows: The motor IIIwhich drives shaft II has a 9,146,895 neutral connection iln connecteddirectly with the negative side of the battery or source 22.

Connection ill! for forward operation of the motor connects with thepositive sideo! source 22 through control contacts "and I; andconnection iilr for reverse operation of the motor similarly connectswith the positive side of the battery through control contacts 2 to andf.

The motor control relay 20 is directly connected with the positive sideof the source 22 and to contact segment i2a of drum switch i2, and thecircuit may be completed through any of the contacts i2ec-h, relaycontacts i8c--h, and the minor selector switch IS, in accordance withspecial conditions; the circuit being continued from switch arm 15c,relay contacts Na and b, on-normal contacts He and d of the dial switchll to the negative side of source 22. Motor control-relay 2i is directlyconnected with the positive side of the source 22 and to contact segmentl2c of drum switch l2, and the circuit is completed as described forrelay 20, the relays 20, 2|, being alternately operative in accordancewith the position of the contact segments I2a and l2c with respect tothe contacts l2e-h on the drum switch, the motor I0 accordingly beingdriven forward or reverse.

The impulse or rotating magnet I of the minor switch I5 is connected atone side directly with the positive side of the source 22, and at theother side with the negative through impulse contacts a and b of thedial switch it. The release magnet H for the minor switch I! isconnected at one side directly with the positive side of the source 22,and at the other side through of!- normal contacts iif and g of theminor switch I! and relay contacts I80 and d to the negative side of thesource 22, the latter contacts controlling tilie application of voltageto the release magnet i i Sequence control relay ll, having a brief timelag as noted, is energized directly from the positive side of the source22, the circuit being com;- pleted through the ofl-normal contacts lieand d of dial switch It to the negative side of the source 22. As theoft-normal contacts will be opened as soon as the dial switch returns tonormal, a holding circuit is provided for relay ll comprising contactsIn and b controlled by the relay itself, and either contacts 20a and bor 2la and b, depending upon which relay 2. or 2| is operated, wherebythe circuit is completed to the 0 negative side of the source 22. e

Sequence control relay ll, having a longer time lag than relay I8, isenergized directly from the positive side of the source 22, the circuitbeing completed through contacts llb and a, and of!- normal contacts Hoand d, to the negative side or source 22, thus operating relay itimmediately pursuant to the functioning of relay II. A portion of theholding circuit for relay i8 is connected with relay it; that is, the.circuit may be completed through relay contacts 204 and b or 2 la and b,whichever may be closed. The slow release feature of relays l8 and I!together with the holding circuits therefor, assure positive operation01' the system, and prevent premature release ot'the contacts controlledby these relays.

The magnetic brake shown schematically at 24 is connected throughseparate motor control relay contacts 200 and d and 2lc and d, in seriesbetween the negative 01' the source 22 and the magnetic brake 24, thecircuit being completed by direct connection to the positive side of thesource 22. Thus if either of the relays 20 or 2| is actuated for drivingthe motor 10, the magnetic brake 2 is The sequence of operation may bedescribed as follows: Supposing. operation has to a position #1, and itis desirod'to chem to a position #3; segment no is at MW contact 12s.The digit-3 is dialed'on dial switch ll, which action first breaks thecircuit through contacts Md, e, and completes the circuit from battery22 through contacts Md, 0, and relay coil ll, operating relay i8.Contacts Ila and b immediately close operating relay ll. Upon release ofthe dial, contacts Ila and b close and open three times, completing thecircuit through rotating magnet it three times and causing minor switcharm lie to step up to contact lic. Upon return 01 the dial to normal,contact is broken between lid and 0, but relays i2 and I! do not releaseinstantaneously due to their slow release action. Contacts Md and eclose completing the circuit from battery 22 through contacts Md and 0,contacts l9b and a, (now closed), minor switch arm lie and, contact lic,contacts lld and e, (now closed), contact i2h, contact seg- !erringconnection from contact ilc through contact lid to contact Ito andcontact I29 on the drum switch i2. A circuit is now complete frombattery 22 through contacts Md and e, b and a, switch arm lie andcontacts llc, lid and 0. contact segment I20 and relay 2|. Relay 20operates immediately completing a circuit from battery 22 throughcontacts 20b and a and relay IO, again holding it operated; relay I! hasnot dropped out as its release time is considerably longer than that oi'relay i8. Operation of relay 20 causes motor I. to rotate in acounterclockwise direction until insulating segment l2b has comeopposite contact i2a at which point the circuit to relay 2. is broken.will open contacts 20a and b and the circuit through relay ll. I

After suiilcient delay, relay i! will drop out opening contacts Ila andb and closing contacts lie and d. A circuit is now completed frombattery 22 through contacts "(and c, contacts I00 and I, and releasemagnet I'Lwhich causes minor switch arm lBe to return to the homeposition. In the home position contacts I50 and I open and remove powerfrom release magnet i! so that the circuit is now ready for anothercycle of operation.

As previously described, the angular positions of shafts 0 are changedfrom those corresponding to position #1 to those corresponding toposition #3 if switch i2 is rotated so that sesment |2b runs fromcontact l2e to contact i2h. and then returns to contact I20. Suchoperation is automatically accomplished by the electrical sequence abovedescribed.

Upon further inspection it will be seen that ii.

' the number 1" or 2 is dialed, motor II will Release of relay 2|shaftsi to position #4, 11 number "3" or 4" is 7 4 dialed, The motorthen stops and if the number dialed was "2" or "3", the motor willreverse and run the shafts to that viously set position is #1 or #4 andthe same number were dialed again, the positions would remain fixed,while if the previous position is #2, and .2 were again dialed, themotor would run to position #1, and then back to #2, the same holdingfor position #3 with respect to #4. This is not objectionable, and isproof that the system is not affected-by mis-dialing for a positionalready had;

Since positioning is effected against a stop, with force applied througha friction clutch, it is not,desired .to have any hunting action due toalternate contacts between one of the con-. tacts l2e-h ,and bothcontact segments Ila and c at anypoint in segments lib and d may beenlarged in circumferential length, contacts l2e-h being relativelypositioned accordingly, in lieu of magnetic brake 24 shown in connectionwith the shaft of motor Ill. This brake is only applied when relays 20and 2| are not operated, and draws but small current from the source 22.

"The difference in release time of relays I8 and I9 is important, as atcertain stages of the op-. eration both of these stages are deenergizedand the continuance of the proper sequence is dependent upon theirproper operation. For example, both relays must hold in when ofl-normalcontacts Md and 0 open until contacts (I and e close, sending currentthrough control switch I! and relay 20 or 2l,:and relay 20 or 2|operates to establish the holding circuitfor the relays l8, It. Again,after the control switch I! has rotated to deenergize the relay 20 or2|, the relays l8 and is are deenergized; now relay l9 must hold longerthan relay I 8 in or 2| may be operated if "2" or "3 number dialed,current being led tacts l8f and g, or Ito and d, to l2, to the relayconcerned. It will be noted further in this instance, that relay I8 isnot again energized, the holding circuit therefor being broken atcontacts Ila, 2). Subsequent deenergization of the motor control relay20 or-2I is final and relay l9 releases in due course, operating todisconnect the minor switch arm from the source, so that the motorcontrol relays will not be operated as the minor switch returns tonormal, upon the immediate operation of the release magnet l While Ihave described my invention in a certain preferred embodiment, I desireit to be understood that modifications may be made therein, and that Iintend no limitations upon my invention except as are imposed by thescope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. In combination, a reversible motor, motor directional control relaysconnected therewith,

has been the through concontrol switch means actuated by the motor forcontrolling theenergization of said relays, separate means including aselector switch and sequence control relay devices connected with theaforesaid means and operative in a predetermined series of operationsfor controlling the operation of the afore-- said motor control relays,and means controlled by said motor control relays for disconnecting saidseparate means when both said relays are deenergized.

2. The combination set forth in claim I includa magnetic brake'devicemechanically conposition. Also, if the prethe cycle. The insulatingorder that relay 20.

switch driven by the 3. The. combination set forth in claim 1 includinga dial impulse switch device and means cooperative therewith forcontrolling the said.

selector switch.

4. A control circuit for a motor actuated 'shaft positioning system,comprising a dial impulse switch and a coaoting minor switch, a drumtype control switch driven by the motor, sequence control relay switchmeans connected between said minor switch and said control switch, asource of power, motor control relay means connected with said source ofpower through said control switch and said minor switch, a slow releasesequence control relay connected with said source of power andcontrolled by said motor control relay means, switch means controlled bythe last said relay and adapted to control the release-of said minorswitch.

5. A control circuit for a motor actuated shaft positioning'system asset forth in claim 4 and including ofi-normal contacts on said dialimpulse switch connected in circuit with the source of power and saidsequence control relay switch means whereby said relay switch means isenergized upon the operation of said dial switch, and a holding circuitfor said relay switch means including contacts controlled by said motorcontrol relay means. a I

6. A control circuit for a motor actuated shaft positioning system asset forth in claim 4 and including off-normal contacts on said dialimpulse switch connected of power and said sequence control relay switchmeans, a holding circuit for said relay switch means includingself-actuated contacts and contacts controlled by a said motor controlrelay means, the slow release sequence. control relay being energizedthrough the self-actuated con-. tacts of said relay switch means andhaving a holding circuit comprising said contacts controlled by saidmotor control relay means, whereby said sequence control relay switchmeans remains deenergized when said self-actuated holding contacts areopened, while said slow release sequence control relay remains actuatedand may be reenergized under control of said motor control relay means.

7. A control circuit for a motor actuated shaft positioning system,comprising a dial impulse switch and a coacting minor switch, acontrolmotor, a source of power, sequence control relay switch means connectedbetween said minor switch and said control switch, motor control relaymeans energized from in circuit with the source,

said source through said control switch and said minor switch, a slowrelease sequence control relay device having contacts connected incircuit with said minor switch and additional contacts adapted tocontrol ed ,to release said contacts with the shaft in set position fordisconnecting the source of power from said minor switch and saidmotorcontrol relay means, whereby the release of said minorfor-establishing an initial control circuit including a source of power,a control switch and motor control relays,

the motor .being operated in onedirection in accordance with theoperation of the the release of said minor switch, said slow releaserelay device being adapt-' motor control relays in said initial controlcircult; a slow release relay adapted to control the operation of saidselector means, and a slow release relay having a longer time delayconstant and relay contacts controlled thereby connected with saidselector means; switch means controlled by said motor control relays forholding both said slow release relays energized during operation of themotor; the first said slow release relay being adapted to release apredetermined time after deenergization and to establish a final controlcircuit including said source of power,

said control switch and said motor control relays, the motor beingoperated in the opposite direction in accordance with the operation ofthe motor control relays in said final control circuit; the said slowrelease relay of longer time delay constant having remained actuatedduring the operation of said final control circuit, being reener' gizedthrough said switch means, and adapted to release a predetermined timeafter deenergization from said final control circuit for dlscon- 1onecting said selector means.

ROBERT E. SAMUEL-SON.

